Yeah, Cat and canalon have it spot on. We're evolving, but there is less selection involved (not none, diseases and lack of resources still affect some parts of the world to a large extent.) and hence we are diversifying.

Evolution is change over time! It does NOT have a goal. Natural selection is the force that imposes limitations on diversity. Today, humans (for most part) are not under natural selection force. This leads to diversity. Diversification IS change over time and, therefore, evolution…

hi,sir: i have a idea: i want to do some experiment of human evaluation with bioinformation on my computer. i want to select one chromosome to do the experiment. do you have some advice for me? i hope i can get the answer of the divergence time between the chinese and westerners.

jmagicking wrote: i have a idea: i want to do some experiment of human evaluation with bioinformation on my computer. i want to select one chromosome to do the experiment. do you have some advice for me? i hope i can get the answer of the divergence time between the chinese and westerners.

Chinese and Westerners are interbreeding (as with most of the human population), and are thus part of the same gene pool. I think this makes them unlikely to diverge/speciate unless the current trend of globalization reverses, and remains that way for many more generations.

Keep in mind that we did not speciate over the 50-60,000 years since the populations originally split apart - and in relation to our biological mechanisms, the differences that have accumulated so far are tiny. If you want to make an estimate assuming no interbreeding, you then need to know the strength of natural selection on each population relative to the other - which is not yet agreed upon (and it's the topic of this thread, after all!) While evolution can certainly act on very short timescales, it requires massive selective forces to do that.

Actually, reading more carefully, I think I might have been too conservative - it seems like the split might have been much earlier than that. I don't think the answer is known with great certainty (though it seems that around 50,000 years is a lower limit, since there are many human artifacts found elsewhere by then).

why i want to know this thing, because i think our genes( biological mechanisms) lead to our culture differece, not the environment.

I don't know enough to comment on that. However, it's definitely something that you would need evidence for, not something you could simply calculate. For example, you could start with looking at children from one population but adopted into another (I'm sure that many such studies have already been done). It's also very hard to get proper, ethical controls for human studies, so you might find information pointing in all directions on some topics.

jmagicking wrote:so, this is another questions about the topic, how to define the Homo sapiens from the biology, whether have a genetic characteristics.

We define species like humans based on reproductive compatibility - if you can produce fertile offspring, you are part of the same species.

Of course, the human genome is different from the genome of any other organism, so you could definitely use genetic characteristics to identify it. For example, no other species has exactly the same collection of FOX genes as humans, or exactly the same collection of CYP genes, etc. However, these do not define the species, because if we found an animal that did have the same sets of genes, that would not make it the same species - only reproductive compatibility allows that.

i have a question is why we select y chromosome or mtdna to analysis human evaluation

Generally because the Y chromosome is only passed down from father to son, and mtDNA is only passed down from mother to daughter. I don't know enough to talk about why this is useful though.

Generally because the Y chromosome is only passed down from father to son, and mtDNA is only passed down from mother to daughter. I don't know enough to talk about why this is useful though.

as you say, so y chromosome and mtdna is more conservitavie than genetic material. euchromosome obey "Law of linkage and crossing over ", so if a chinese man marry a european womom, the euchromosomes have more mutations than y chromosome and mtdna. that is my understanding